Eyewear display having offset bonding

ABSTRACT

Eyewear including a multi-layered display having an adhesive bonding the layers together at an offset distance inward from an outer edge of the layers. The display has an image display layer, such as an optical waveguide in one example, and a pair of layers encompassing the image display layer and which may comprise optically transparent substrates, such as glass. A respective adhesive is positioned the offset distance inward from the outer edge of the display layer between the image display layer and each of the pair of layers to reduce stress in the display. Each of the adhesives may be a continuous bead such that there is no adhesive between the pair of layers and the image display layer at the outer edges. In one example, the offset distance may be at least double the thickness of the image display layer to reduce stress in the image display layer.

TECHNICAL FIELD

The present subject matter relates to an eyewear device, e.g., smartglasses and see-through displays.

BACKGROUND

Portable eyewear devices, such as smart glasses, headwear, and headgearcurrently available include electronics such as cameras and displays.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations, by way ofexample only, not by way of limitations. In the figures, like referencenumerals refer to the same or similar elements.

FIG. 1A is a side view of an example hardware configuration of aneyewear device, which shows a right optical assembly with an imagedisplay, and field of view adjustments are applied to a user interfacepresented on the image display based on detected head or eye movement bya user;

FIG. 1B is a top cross-sectional view of a temple of the eyewear deviceof FIG. 1A depicting a visible light camera, a head movement tracker fortracking the head movement of the user of the eyewear device, and acircuit board;

FIG. 2A is a rear view of an example hardware configuration of aneyewear device, which includes an eye scanner on a frame, for use in asystem for identifying a user of the eyewear device;

FIG. 2B is a rear view of an example hardware configuration of anothereyewear device, which includes an eye scanner on a temple, for use in asystem for identifying a user of the eyewear device;

FIGS. 2C and 2D are rear views of example hardware configurations of theeyewear device, including two different types of image displays.

FIG. 3 shows a rear perspective view of the eyewear device of FIG. 2Adepicting an infrared emitter, an infrared camera, a frame front, aframe back, and a circuit board;

FIG. 4A is a cross-sectional view taken through the infrared emitter andthe frame of the eyewear device of FIG. 3 ;

FIG. 4B and FIG. 4C illustrate the waveguides of the displays may beformed as a waveguide stack having multiple layers;

FIG. 4D illustrates a structure analysis of the waveguide stack of FIG.4C, and of the waveguide stack of FIG. 4E;

FIG. 4E, FIG. 4F and FIG. 4G illustrate a bonded waveguide stack thatminimizes the stress at the waveguide edge by positioning an adhesiveinward from the outer edge of the display;

FIG. 4H illustrates the waveguide stack secured to the frame, whereinthe adhesive between the waveguide stack and the frame is offsetdistance OFF from the edge of the waveguide stack;

FIG. 4I illustrates the stress at the edges of the waveguide stack shownin FIG. 4C;

FIG. 4J illustrates the stress at the edges of the waveguide stack ofFIG. 4E, illustrating a reduced stress compared to the example of FIG.4C;

FIG. 5 illustrates detecting eye gaze direction;

FIG. 6 illustrates detecting eye position;

FIG. 7 depicts an example of visible light captured by the left visiblelight camera as a left raw image and visible light captured by the rightvisible light camera as a right raw image;

FIG. 8 illustrates a method of producing the waveguide stack of FIG. 4E;

FIG. 9 illustrates a block diagram of electronic components of theeyewear device and a mobile device and server system connected viavarious networks; and

FIG. 10 illustrates an example wearable device (e.g., an eyewear device)with visual user input.

DETAILED DESCRIPTION

Eyewear including a multi-layered display having an adhesive bonding thelayers together at an offset distance inward from an outer edge of thelayers. The display has an image display layer, such as an opticalwaveguide in one example, and a pair of layers encompassing the imagedisplay layer and which may comprise optically transparent substrates,such as glass. A respective adhesive is positioned the offset distanceinward from the outer edge of the image display layer between the imagedisplay layer and each of the pair of layers to reduce stress in thedisplay. Each of the adhesives may be a continuous bead such that thereis no adhesive between the pair of layers and the image display layer atthe outer edges. Due to the offset distance of the adhesive, at simplysupported locations (free ends), there is no bending moment, hence thereis no bending stress, thus making the waveguide edge stress free duringbending. In one example, the offset distance may be at least double thethickness of the image display layer to reduce stress in the imagedisplay layer.

Additional objects, advantages and novel features of the examples willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing and the accompanying drawings or may be learned by productionor operation of the examples. The objects and advantages of the presentsubject matter may be realized and attained by means of themethodologies, instrumentalities and combinations particularly pointedout in the appended claims.

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. However, it should be apparent to those skilledin the art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures, components,and circuitry have been described at a relatively high-level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentteachings.

The term “coupled” as used herein refers to any logical, optical,physical or electrical connection, link or the like by which signals orlight produced or supplied by one system element are imparted to anothercoupled element. Unless described otherwise, coupled elements or devicesare not necessarily directly connected to one another and may beseparated by intermediate components, elements or communication mediathat may modify, manipulate or carry the light or signals.

The orientations of the eyewear device, associated components and anycomplete devices incorporating an eye scanner and camera such as shownin any of the drawings, are given by way of example only, forillustration and discussion purposes. In operation for a particularvariable optical processing application, the eyewear device may beoriented in any other direction suitable to the particular applicationof the eyewear device, for example up, down, sideways, or any otherorientation. Also, to the extent used herein, any directional term, suchas front, rear, inwards, outwards, towards, left, right, lateral,longitudinal, up, down, upper, lower, top, bottom and side, are used byway of example only, and are not limiting as to direction or orientationof any optic or component of an optic constructed as otherwise describedherein.

Reference now is made in detail to the examples illustrated in theaccompanying drawings and discussed below.

FIG. 1A is a side view of an example hardware configuration of aneyewear device 100, which includes a right optical assembly 180B with animage display 180D (FIG. 2A). Eyewear device 100 includes multiplevisible light cameras 114A-B (FIG. 7 ) that form a stereo camera, ofwhich the right visible light camera 114B is located on a right temple110B.

The left and right visible light cameras 114A-B have an image sensorthat is sensitive to the visible light range wavelength. Each of thevisible light cameras 114A-B have a different frontward facing angle ofcoverage, for example, visible light camera 114B has the depicted angleof coverage 111B. The angle of coverage is an angle range which theimage sensor of the visible light camera 114A-B picks up electromagneticradiation and generates images. Examples of such visible lights camera114A-B include a high-resolution complementary metal-oxide-semiconductor(CMOS) image sensor and a video graphic array (VGA) camera, such as 640p(e.g., 640×480 pixels for a total of 0.3 megapixels), 720p, or 1080p.Image sensor data from the visible light cameras 114A-B are capturedalong with geolocation data, digitized by an image processor, and storedin a memory.

To provide stereoscopic vision, visible light cameras 114A-B may becoupled to an image processor (element 912 of FIG. 9 ) for digitalprocessing along with a timestamp in which the image of the scene iscaptured. Image processor 912 includes circuitry to receive signals fromthe visible light camera 114A-B and process those signals from thevisible light cameras 114A-B into a format suitable for storage in thememory (element 934 of FIG. 9 ). The timestamp can be added by the imageprocessor 912 or other processor, which controls operation of thevisible light cameras 114A-B. Visible light cameras 114A-B allow thestereo camera to simulate human binocular vision. Stereo cameras providethe ability to reproduce three-dimensional images (element 715 of FIG. 7) based on two captured images (elements 758A-B of FIG. 7 ) from thevisible light cameras 114A-B, respectively, having the same timestamp.Such three-dimensional images 715 allow for an immersive life-likeexperience, e.g., for virtual reality or video gaming. For stereoscopicvision, the pair of images 758A-B are generated at a given moment intime—one image for each of the left and right visible light cameras114A-B. When the pair of generated images 758A-B from the frontwardfacing angles of coverage 111A-B of the left and right visible lightcameras 114A-B are stitched together (e.g., by the image processor 912),depth perception is provided by the optical assembly 180A-B.

In an example, a user interface field of view adjustment system includesthe eyewear device 100. The eyewear device 100 includes a frame 105, aright temple 110B extending from a right lateral side 170B of the frame105, and a see-through image display 180D (FIGS. 2A-B) comprisingoptical assembly 180B to present a graphical user interface to a user.The eyewear device 100 includes the left visible light camera 114Aconnected to the frame 105 or the left temple 110A to capture a firstimage of the scene. Eyewear device 100 further includes the rightvisible light camera 114B connected to the frame 105 or the right temple110B to capture (e.g., simultaneously with the left visible light camera114A) a second image of the scene which partially overlaps the firstimage. Although not shown in FIGS. 1A-B, the user interface field ofview adjustment system further includes the processor 932 coupled to theeyewear device 100 and connected to the visible light cameras 114A-B,the memory 934 accessible to the processor 932, and programming in thememory 934, for example in the eyewear device 100 itself or another partof the user interface field of view adjustment system.

Although not shown in FIG. 1A, the eyewear device 100 also includes ahead movement tracker (element 109 of FIG. 1B) or an eye movementtracker (element 213 of FIGS. 2A-B). Eyewear device 100 further includesthe see-through image displays 180C-D of optical assembly 180A-B forpresenting a sequence of displayed images, and an image display driver(element 942 of FIG. 9 ) coupled to the see-through image displays180C-D of optical assembly 180A-B to control the image displays 180C-Dof optical assembly 180A-B to present the sequence of displayed images715, which are described in further detail below. Eyewear device 100further includes the memory 934 and the processor 932 having access tothe image display driver 942 and the memory 934. Eyewear device 100further includes programming (element 934 of FIG. 9 ) in the memory.Execution of the programming by the processor 932 configures the eyeweardevice 100 to perform functions, including functions to present, via thesee-through image displays 180C-D, an initial displayed image of thesequence of displayed images, the initial displayed image having aninitial field of view corresponding to an initial head direction or aninitial eye gaze direction (element 230 of FIG. 5 ).

Execution of the programming by the processor 932 further configures theeyewear device 100 to detect movement of a user of the eyewear deviceby: (i) tracking, via the head movement tracker (element 109 of FIG.1B), a head movement of a head of the user, or (ii) tracking, via an eyemovement tracker (element 113, 213 of FIGS. 2A-B, FIG. 5 ), an eyemovement of an eye of the user of the eyewear device 100. Execution ofthe programming by the processor 932 further configures the eyeweardevice 100 to determine a field of view adjustment to the initial fieldof view of the initial displayed image based on the detected movement ofthe user. The field of view adjustment includes a successive field ofview corresponding to a successive head direction or a successive eyedirection. Execution of the programming by the processor 932 furtherconfigures the eyewear device 100 to generate a successive displayedimage of the sequence of displayed images based on the field of viewadjustment. Execution of the programming by the processor 932 furtherconfigures the eyewear device 100 to present, via the see-through imagedisplays 180C-D of the optical assembly 180A-B, the successive displayedimages.

FIG. 1B is a top cross-sectional view of the temple of the eyeweardevice 100 of FIG. 1A depicting the right visible light camera 114B, ahead movement tracker 109, and a circuit board. Construction andplacement of the left visible light camera 114A is substantially similarto the right visible light camera 114B, except the connections andcoupling are on the left lateral side 170A. As shown, the eyewear device100 includes the right visible light camera 114B and a circuit board,which may be a flexible printed circuit board (PCB) 140. The right hinge126B connects the right temple 110B to a right temple 125B of theeyewear device 100. In some examples, components of the right visiblelight camera 114B, the flexible PCB 140, or other electrical connectorsor contacts may be located on the right temple 125B or the right hinge126B.

As shown, eyewear device 100 has a head movement tracker 109, whichincludes, for example, an inertial measurement unit (IMU). An inertialmeasurement unit is an electronic device that measures and reports abody's specific force, angular rate, and sometimes the magnetic fieldsurrounding the body, using a combination of accelerometers andgyroscopes, sometimes also magnetometers. The inertial measurement unitworks by detecting linear acceleration using one or more accelerometersand rotational rate using one or more gyroscopes. Typical configurationsof inertial measurement units contain one accelerometer, gyro, andmagnetometer per axis for each of the three axes: horizontal axis forleft-right movement (X), vertical axis (Y) for top-bottom movement, anddepth or distance axis for up-down movement (Z). The accelerometerdetects the gravity vector. The magnetometer defines the rotation in themagnetic field (e.g., facing south, north, etc.) like a compass whichgenerates a heading reference. The three accelerometers to detectacceleration along the horizontal, vertical, and depth axis definedabove, which can be defined relative to the ground, the eyewear device100, or the user wearing the eyewear device 100.

Eyewear device 100 detects movement of the user of the eyewear device100 by tracking, via the head movement tracker 109, the head movement ofthe head of the user. The head movement includes a variation of headdirection on a horizontal axis, a vertical axis, or a combinationthereof from the initial head direction during presentation of theinitial displayed image on the image display. In one example, tracking,via the head movement tracker 109, the head movement of the head of theuser includes measuring, via the inertial measurement unit 109, theinitial head direction on the horizontal axis (e.g., X axis), thevertical axis (e.g., Y axis), or the combination thereof (e.g.,transverse or diagonal movement). Tracking, via the head movementtracker 109, the head movement of the head of the user further includesmeasuring, via the inertial measurement unit 109, a successive headdirection on the horizontal axis, the vertical axis, or the combinationthereof during presentation of the initial displayed image.

Tracking, via the head movement tracker 109, the head movement of thehead of the user further includes determining the variation of headdirection based on both the initial head direction and the successivehead direction. Detecting movement of the user of the eyewear device 100further includes in response to tracking, via the head movement tracker109, the head movement of the head of the user, determining that thevariation of head direction exceeds a deviation angle threshold on thehorizontal axis, the vertical axis, or the combination thereof. Thedeviation angle threshold is between about 3° to 10°. As used herein,the term “about” when referring to an angle means±10% from the statedamount.

Variation along the horizontal axis slides three-dimensional objects,such as characters, Bitmojis, application icons, etc. in and out of thefield of view by, for example, hiding, unhiding, or otherwise adjustingvisibility of the three-dimensional object. Variation along the verticalaxis, for example, when the user looks upwards, in one example, displaysweather information, time of day, date, calendar appointments, etc. Inanother example, when the user looks downwards on the vertical axis, theeyewear device 100 may power down.

The right temple 110B includes temple body 211 and a temple cap, withthe temple cap omitted in the cross-section of FIG. 1B. Disposed insidethe right temple 110B are various interconnected circuit boards, such asPCBs or flexible PCBs, that include controller circuits for rightvisible light camera 114B, microphone(s) 130, speaker(s) 132, low-powerwireless circuitry (e.g., for wireless short-range network communicationvia Bluetooth™), high-speed wireless circuitry (e.g., for wireless localarea network communication via WiFi).

The right visible light camera 114B is coupled to or disposed on theflexible PCB 240 and covered by a visible light camera cover lens, whichis aimed through opening(s) formed in the right temple 110B. In someexamples, the frame 105 connected to the right temple 110B includes theopening(s) for the visible light camera cover lens. The frame 105includes a front-facing side configured to face outwards away from theeye of the user. The opening for the visible light camera cover lens isformed on and through the front-facing side. In the example, the rightvisible light camera 114B has an outwards facing angle of coverage 111Bwith a line of sight or perspective of the right eye of the user of theeyewear device 100. The visible light camera cover lens can also beadhered to an outwards facing surface of the right temple 110B in whichan opening is formed with an outwards facing angle of coverage, but in adifferent outwards direction. The coupling can also be indirect viaintervening components.

Left (first) visible light camera 114A is connected to the leftsee-through image display 180C of left optical assembly 180A to generatea first background scene of a first successive displayed image. Theright (second) visible light camera 114B is connected to the rightsee-through image display 180D of right optical assembly 180B togenerate a second background scene of a second successive displayedimage. The first background scene and the second background scenepartially overlap to present a three-dimensional observable area of thesuccessive displayed image.

Flexible PCB 140 is disposed inside the right temple 110B and is coupledto one or more other components housed in the right temple 110B.Although shown as being formed on the circuit boards of the right temple110B, the right visible light camera 114B can be formed on the circuitboards of the left temple 110A, the temples 125A-B, or frame 105.

FIG. 2A is a rear view of an example hardware configuration of aneyewear device 100, which includes an eye scanner 113 on a frame 105,for use in a system for determining an eye position and gaze directionof a wearer/user of the eyewear device 100. As shown in FIG. 2A, theeyewear device 100 is in a form configured for wearing by a user, whichare eyeglasses in the example of FIG. 2A. The eyewear device 100 cantake other forms and may incorporate other types of frameworks, forexample, a headgear, a headset, or a helmet.

In the eyeglasses example, eyewear device 100 includes the frame 105which includes the left rim 107A connected to the right rim 107B via thebridge 106 adapted for a nose of the user. The left and right rims107A-B include respective apertures 175A-B which hold the respectiveoptical element 180A-B, such as a transparent lens, and the see-throughdisplays 180C-D interposed therebetween as shown in FIG. 4B. As usedherein, the term lens is meant to cover transparent or translucentpieces of glass or plastic having curved and flat surfaces that causelight to converge/diverge or that cause little or noconvergence/divergence.

Although shown as having two optical elements 180A-B, the eyewear device100 can include other arrangements, such as a single optical elementdepending on the application or intended user of the eyewear device 100.As further shown, eyewear device 100 includes the left temple 110Aadjacent the left lateral side 170A of the frame 105 and the righttemple 110B adjacent the right lateral side 170B of the frame 105. Thetemples 110A-B may be integrated into the frame 105 on the respectivesides 170A-B (as illustrated) or implemented as separate componentsattached to the frame 105 on the respective sides 170A-B. Alternatively,the temples 110A-B may be integrated into temples (not shown) attachedto the frame 105.

In the example of FIG. 2A, the eye scanner 113 includes an infraredemitter 115 and an infrared camera 120. Visible light cameras typicallyinclude a blue light filter to block infrared light detection, in anexample, the infrared camera 120 is a visible light camera, such as alow-resolution video graphic array (VGA) camera (e.g., 640×480 pixelsfor a total of 0.3 megapixels), with the blue filter removed. Theinfrared emitter 115 and the infrared camera 120 are co-located on theframe 105, for example, both are shown as connected to the upper portionof the left rim 107A. The frame 105 or one or more of the left and righttemples 110A-B include a circuit board (not shown) that includes theinfrared emitter 115 and the infrared camera 120. The infrared emitter115 and the infrared camera 120 can be connected to the circuit board bysoldering, for example.

Other arrangements of the infrared emitter 115 and infrared camera 120can be implemented, including arrangements in which the infrared emitter115 and infrared camera 120 are both on the right rim 107B, or indifferent locations on the frame 105, for example, the infrared emitter115 is on the left rim 107A and the infrared camera 120 is on the rightrim 107B. In another example, the infrared emitter 115 is on the frame105 and the infrared camera 120 is on one of the temples 110A-B, or viceversa. The infrared emitter 115 can be connected essentially anywhere onthe frame 105, left temple 110A, or right temple 110B to emit a patternof infrared light. Similarly, the infrared camera 120 can be connectedessentially anywhere on the frame 105, left temple 110A, or right temple110B to capture at least one reflection variation in the emitted patternof infrared light.

The infrared emitter 115 and infrared camera 120 are arranged to faceinwards towards an eye of the user with a partial or full field of viewof the eye in order to identify the respective eye position and gazedirection. For example, the infrared emitter 115 and infrared camera 120are positioned directly in front of the eye, in the upper part of theframe 105 or in the temples 110A-B at either ends of the frame 105.

FIG. 2B is a rear view of an example hardware configuration of anothereyewear device 200. In this example configuration, the eyewear device200 is depicted as including an eye scanner 213 on a right temple 210B.As shown, an infrared emitter 215 and an infrared camera 220 areco-located on the right temple 210B. It should be understood that theeye scanner 213 or one or more components of the eye scanner 213 can belocated on the left temple 210A and other locations of the eyeweardevice 200, for example, the frame 105. The infrared emitter 215 andinfrared camera 220 are like that of FIG. 2A, but the eye scanner 213can be varied to be sensitive to different light wavelengths asdescribed previously in FIG. 2A.

Similar to FIG. 2A, the eyewear device 200 includes a frame 105 whichincludes a left rim 107A which is connected to a right rim 107B via abridge 106; and the left and right rims 107A-B include respectiveapertures which hold the respective optical elements 180A-B comprisingthe see-through display 180C-D.

FIGS. 2C-D are rear views of example hardware configurations of theeyewear device 200, including two different types of see-through imagedisplays 180C-D. In one example, these see-through image displays 180C-Dof optical assembly 180A-B include an integrated image display. As shownin FIG. 2C, the optical assemblies 180A-B includes a suitable displaymatrix 180C-D of any suitable type, such as a liquid crystal display(LCD), an organic light-emitting diode (OLED) display, a waveguidedisplay, or any other such display. The optical assembly 180A-B alsoincludes an optical layer or layers 176, which can include lenses,optical coatings, prisms, mirrors, waveguides, optical strips, and otheroptical components in any combination. The optical layers 176A-N caninclude a prism having a suitable size and configuration and including afirst surface for receiving light from display matrix and a secondsurface for emitting light to the eye of the user. The prism of theoptical layers 176A-N extends over all or at least a portion of therespective apertures 175A-B formed in the left and right rims 107A-B topermit the user to see the second surface of the prism when the eye ofthe user is viewing through the corresponding left and right rims107A-B. The first surface of the prism of the optical layers 176A-Nfaces upwardly from the frame 105 and the display matrix overlies theprism so that photons and light emitted by the display matrix impingethe first surface. The prism is sized and shaped so that the light isrefracted within the prism and is directed towards the eye of the userby the second surface of the prism of the optical layers 176A-N. In thisregard, the second surface of the prism of the optical layers 176A-N canbe convex to direct the light towards the center of the eye. The prismcan optionally be sized and shaped to magnify the image projected by thesee-through image displays 180C-D, and the light travels through theprism so that the image viewed from the second surface is larger in oneor more dimensions than the image emitted from the see-through imagedisplays 180C-D.

In another example, the see-through image displays 180C-D of opticalassembly 180A-B include a projection image display as shown in FIG. 2D.The optical assembly 180A-B includes a laser projector 150, which is athree-color laser projector using a scanning mirror or galvanometer.During operation, an optical source such as a laser projector 150 isdisposed in or on one of the temples 125A-B of the eyewear device 100.Optical assembly 180A-B includes one or more optical strips 155A-Nspaced apart across the width of the lens of the optical assembly 180A-Bor across a depth of the lens between the front surface and the rearsurface of the lens.

As the photons projected by the laser projector 150 travel across thelens of the optical assembly 180A-B, the photons encounter the opticalstrips 155A-N. When a particular photon encounters a particular opticalstrip, the photon is either redirected towards the user's eye, or itpasses to the next optical strip. A combination of modulation of laserprojector 150, and modulation of optical strips, may control specificphotons or beams of light. In an example, a processor controls opticalstrips 155A-N by initiating mechanical, acoustic, or electromagneticsignals. Although shown as having two optical assemblies 180A-B, theeyewear device 100 can include other arrangements, such as a single orthree optical assemblies, or the optical assembly 180A-B may havearranged different arrangement depending on the application or intendeduser of the eyewear device 100.

As further shown in FIGS. 2C-D, eyewear device 100 includes a lefttemple 110A adjacent the left lateral side 170A of the frame 105 and aright temple 110B adjacent the right lateral side 170B of the frame 105.The temples 110A-B may be integrated into the frame 105 on therespective lateral sides 170A-B (as illustrated) or implemented asseparate components attached to the frame 105 on the respective sides170A-B. Alternatively, the temples 110A-B may be integrated into temples125A-B attached to the frame 105.

In one example, the see-through image displays include the firstsee-through image display 180C and the second see-through image display180D. Eyewear device 100 includes first and second apertures 175A-Bwhich hold the respective first and second optical assembly 180A-B. Thefirst optical assembly 180A includes the first see-through image display180C (e.g., a display matrix of FIG. 2C or optical strips 155A-N′ and aprojector 150A). The second optical assembly 180B includes the secondsee-through image display 180D e.g., a display matrix of FIG. 2C oroptical strips 155A-N″ and a projector 150B). The successive field ofview of the successive displayed image includes an angle of view betweenabout 15° to 30, and more specifically 24°, measured horizontally,vertically, or diagonally. The successive displayed image having thesuccessive field of view represents a combined three-dimensionalobservable area visible through stitching together of two displayedimages presented on the first and second image displays.

As used herein, “an angle of view” describes the angular extent of thefield of view associated with the displayed images presented on each ofthe left and right image displays 180C-D of optical assembly 180A-B. The“angle of coverage” describes the angle range that a lens of visiblelight cameras 114A-B or infrared camera 220 can image. Typically, theimage circle produced by a lens is large enough to cover the film orsensor completely, possibly including some vignetting (i.e., a reductionof an image's brightness or saturation toward the periphery compared tothe image center). If the angle of coverage of the lens does not fillthe sensor, the image circle will be visible, typically with strongvignetting toward the edge, and the effective angle of view will belimited to the angle of coverage. The “field of view” is intended todescribe the field of observable area which the user of the eyeweardevice 100 can see through his or her eyes via the displayed imagespresented on the left and right image displays 180C-D of the opticalassembly 180A-B. Image display 180C of optical assembly 180A-B can havea field of view with an angle of coverage between 15° to 30°, forexample 24°, and have a resolution of 480×480 pixels.

FIG. 3 shows a rear perspective view of the eyewear device of FIG. 2A.The eyewear device 100 includes an infrared emitter 215, infrared camera220, a frame front 330, a frame back 335, and a circuit board 340. Itcan be seen in FIG. 3 that the upper portion of the left rim of theframe of the eyewear device 100 includes the frame front 330 and theframe back 335. An opening for the infrared emitter 215 is formed on theframe back 335.

As shown in the encircled cross-section 4 in the upper middle portion ofthe left rim of the frame, a circuit board, which is a flexible PCB 340,is sandwiched between the frame front 330 and the frame back 335. Alsoshown in further detail is the attachment of the left temple 110A to theleft temple 325A via the left hinge 126A. In some examples, componentsof the eye movement tracker 213, including the infrared emitter 215, theflexible PCB 340, or other electrical connectors or contacts may belocated on the left temple 325A or the left hinge 126A.

FIG. 4A is a cross-sectional view through the infrared emitter 215 andthe frame corresponding to the encircled cross-section 4 of the eyeweardevice of FIG. 3 . Multiple layers of the eyewear device 100 areillustrated in the cross-section of FIG. 4A, as shown the frame includesthe frame front 330 and the frame back 335. The flexible PCB 340 isdisposed on the frame front 330 and connected to the frame back 335. Theinfrared emitter 215 is disposed on the flexible PCB 340 and covered byan infrared emitter cover lens 445. For example, the infrared emitter215 is reflowed to the back of the flexible PCB 340. Reflowing attachesthe infrared emitter 215 to contact pad(s) formed on the back of theflexible PCB 340 by subjecting the flexible PCB 340 to controlled heatwhich melts a solder paste to connect the two components. In oneexample, reflowing is used to surface mount the infrared emitter 215 onthe flexible PCB 340 and electrically connect the two components.However, it should be understood that through-holes can be used toconnect leads from the infrared emitter 215 to the flexible PCB 340 viainterconnects, for example.

The frame back 335 includes an infrared emitter opening 450 for theinfrared emitter cover lens 445. The infrared emitter opening 450 isformed on a rear-facing side of the frame back 335 that is configured toface inwards towards the eye of the user. In the example, the flexiblePCB 340 can be connected to the frame front 330 via the flexible PCBadhesive 460. The infrared emitter cover lens 445 can be connected tothe frame back 335 via infrared emitter cover lens adhesive 455. Thecoupling can also be indirect via intervening components.

The displays 180C and 180D, including waveguides in one example, areimportant components of eyewear 100, and they are relatively weakmechanically. One example material for the waveguide is glass. A cuttingprocess may reduce (roughly about 70% reduction) the strength along theedges of the waveguide.

As illustrated in FIG. 4B and FIG. 4C, the waveguides of displays 180Cand 180D may be formed as a waveguide stack 465 having multiple layers.FIG. 4B is a downward looking cross-sectional view taken along line 4 inFIG. 2A, and FIG. 4C illustrates an enlarged view of the waveguide stack465 of FIG. 4B. One method of bonding the layers in the waveguide stack465 is using a wide adhesive 466 at the edges of the layers of thewaveguide stack 465, which creates stresses at the waveguide stack edgeduring bending of frame 105, and during a free drop, such as falling tothe floor with impact. The waveguide stack 465 may include two glasssubstrates 468 and 470 that are not chemically strengthened, astypically seen in glass covers of mobile phones/tablets. In addition,the cutting process reduces the waveguide edge strength significantlycompared to the base material strength, typically about ⅓rd. Thisresults in a relatively “poor” drop test performance where the glasssubstrate waveguides end up breaking at very low drop heights making itchallenging to meet product reliability requirements.

The waveguide stack 465 may have three layers forming the waveguidestack, including glass substrates 468 and 470 encompassing andsandwiching an image display layer including a waveguide 472 interposedtherebetween. The layers are bonded at their edges using 2 mm wide and0.05 mm to 0.15 mm thick adhesive 466. Then, the waveguide stack 465 isbonded at its edge to the frame 105 using a 2 mm wide and 0.25 mm thickadhesive. A wide adhesive, and in addition ending at the edge of thewaveguide stack 465, makes the waveguide stack 465 a Fixed Boundarystructure in structure analysis, where the stresses of the waveguidestack 465 are generally high, as shown at 476 in FIG. 4D.

Referring to FIG. 4E, FIG. 4F and FIG. 4G, this disclosure provides abonded waveguide stack 480 and method that avoids or minimizes thestress at the waveguide edge. The width W of an adhesive 482 isdecreased as compared to the adhesive in the example of FIG. 4C, theadhesive thickness T increased, and the location of the adhesive 482 isoffset inward from a waveguide edge 484 a distance OFF that ends wellinside the waveguide edge 484, making the waveguide stack 480 a simplysupported structure in structure analysis as shown at 478 in FIG. 4D.Due to the offset distance OFF of the adhesive 482, at simply supportedlocations (free ends), there is no bending moment, hence there is nobending stress, thus making the waveguide edge stress free duringbending.

As shown, the waveguide display assembly 180D, including the waveguidestack 480 in this example, includes an image display layer includingwaveguide 190, and glass substrates 192 and 194 adhesively secured toand sandwiching the waveguide 190. Each of the optically transparentglass substrates 192 and 194 are spaced from waveguide 190 by therespective adhesive 482 to create air gaps 196 and 198 between thewaveguide 190 and each of the glass substrates 192 and 194 to achievethe necessary optical stack-up, and to encapsulate opticalnano-structure gratings that may be included on the waveguide 190 forreliability purposes.

As shown in FIG. 4F, the adhesive offset distance OFF is at least twicethe thickness of the waveguide 190 to reduce or minimize the stress atthe edges of the waveguide stack 480, forming a simply supportedstructure as illustrated at 478 in FIG. 4D. As shown in FIG. 4G, theadhesive 482 has a width W that is offset inward distance OFF from theedge of waveguide stack 480. In an example, the adhesive width W may be1 mm, the adhesive thickness may be 0.5 mm, and the adhesive offset OFFmay be 6 mm where the thickness of the waveguide 190 is 3 mm.

FIG. 4H illustrates the waveguide stack 480 secured to the frame 105,wherein the adhesive 482 between the waveguide stack 480 and frame 105is offset distance OFF from the edge of the waveguide stack 480.

FIG. 4I illustrates the stress at the edges of the waveguide stack 465,illustrating a maximum stress of 132 Mpa for the example of FIG. 4C.

FIG. 4J illustrates the stress at the edges of the waveguide stack 480,illustrating a reduce stress of 73 Mpa, which is a stress reduction ofabout 45% compared to the example of FIG. 4C.

In an example, the processor 932 utilizes eye tracker 213 to determinean eye gaze direction 230 of a wearer's eye 234 as shown in FIG. 5 , andan eye position 236 of the wearer's eye 234 within an eyebox as shown inFIG. 6 . The eye tracker 213 is a scanner which uses infrared lightillumination (e.g., near-infrared, short-wavelength infrared,mid-wavelength infrared, long-wavelength infrared, or far infrared) tocaptured image of reflection variations of infrared light from the eye234 to determine the gaze direction 230 of a pupil 232 of the eye 234,and also the eye position 236 with respect to the see-through display180D.

FIG. 7 depicts an example of capturing visible light with cameras.Visible light is captured by the left visible light camera 114A with aleft visible light camera field of view 111A as a left raw image 758A.Visible light is captured by the right visible light camera 114B with aright visible light camera field of view 111B as a right raw image 758B.Based on processing of the left raw image 758A and the right raw image758B, a three-dimensional depth map 715 of a three-dimensional scene,referred to hereafter as an image, is generated by processor 932.

FIG. 8 is a flowchart 800 illustrating a method of producing thewaveguide stack 480, and also attaching the waveguide stack 480 to frame105 of eyewear 100.

At block 802, a first continuous bead of adhesive 482 is applied to thewaveguide 190 the offset distance OFF from the edge of the waveguide190, such as by a dispensing machine. The adhesive 482 has width W, andthickness T as described and shown with respect to FIG. 4G.

At block 804, the glass substrate 192 is attached to the waveguide 190by a placement tool such that the glass substrate 192 is securelyattached to the waveguide 190, such that the glass substrate 192 isspaced from the waveguide 190 by the air gap 196, as shown in FIG. 4F.The air gap 196 achieves the necessary optical stack-up, and whichencapsulates optical nano-structure gratings that may be included on thewaveguide 190 for reliability purposes.

At block 806, a second continuous bead of adhesive 482 is applied to thewaveguide 190 the offset distance OFF from the edge of the waveguide 190by a dispensing machine, on the opposite side of the waveguide 190having the first bead of adhesive 482. This adhesive 482 also has thewidth W, and thickness T as described and shown with respect to FIG. 4G,and such that the first and second beads of adhesive 482 are verticallyaligned with each other.

At block 808, the glass substrate 194 is attached to the waveguide 190by a placement machine such that the glass substrate 194 is attached tothe waveguide 190, such that the glass substrate 194 is spaced from thewaveguide 190 by the air gap 198, as shown in FIG. 4F. The air gap 198achieves the necessary optical stack-up, and which encapsulates opticalnano-structure gratings that may be included on the waveguide 190 forreliability purposes. This completes the assembly of the waveguide stack480.

At block 810, the waveguide stack 480 is attached to the frame 105 by abead of adhesive 482. As shown in FIG. 4F, the glass substrate 194 ispositioned adjacent the inside edge of frame 105.

FIG. 9 depicts a high-level functional block diagram including exampleelectronic components disposed in eyewear 100 and 100. The illustratedelectronic components include the processor 932, the memory 934, and thesee-through image display 180C and 180D.

Memory 934 includes instructions for execution by processor 932 toimplement functionality of eyewear 100/100, including instructions forprocessor 932 to control in the image 715. Processor 932 receives powerfrom battery (not shown) and executes the instructions stored in memory934, or integrated with the processor 932 on-chip, to performfunctionality of eyewear 100/100, and communicating with externaldevices via wireless connections.

A user interface adjustment system 900 includes a wearable device, whichis the eyewear device 100 with an eye movement tracker 213 (e.g., shownas infrared emitter 215 and infrared camera 220 in FIG. 2B). Userinterface adjustments system 900 also includes a mobile device 990 and aserver system 998 connected via various networks. Mobile device 990 maybe a smartphone, tablet, laptop computer, access point, or any othersuch device capable of connecting with eyewear device 100 using both alow-power wireless connection 925 and a high-speed wireless connection937. Mobile device 990 is connected to server system 998 and network995. The network 995 may include any combination of wired and wirelessconnections.

Eyewear device 100 includes at least two visible light cameras 114A-B(one associated with the left lateral side 170A and one associated withthe right lateral side 170B). Eyewear device 100 further includes twosee-through image displays 180C-D of the optical assembly 180A-B (oneassociated with the left lateral side 170A and one associated with theright lateral side 170B). Eyewear device 100 also includes image displaydriver 942, image processor 912, low-power circuitry 920, and high-speedcircuitry 930. The components shown in FIG. 9 for the eyewear device 100are located on one or more circuit boards, for example a PCB or flexiblePCB, in the temples. Alternatively, or additionally, the depictedcomponents can be located in the temples, frames, hinges, or bridge ofthe eyewear device 100. Left and right visible light cameras 114A-B caninclude digital camera elements such as a complementarymetal-oxide-semiconductor (CMOS) image sensor, charge coupled device, alens, or any other respective visible or light capturing elements thatmay be used to capture data, including images of scenes with unknownobjects.

Eye movement tracking programming 945 implements the user interfacefield of view adjustment instructions, including, to cause the eyeweardevice 100 to track, via the eye movement tracker 213, the eye movementof the eye of the user of the eyewear device 100. Other implementedinstructions (functions) cause the eyewear device 100 to determine, afield of view adjustment to the initial field of view of an initialdisplayed image based on the detected eye movement of the usercorresponding to a successive eye direction. Further implementedinstructions generate a successive displayed image of the sequence ofdisplayed images based on the field of view adjustment. The successivedisplayed image is produced as visible output to the user via the userinterface. This visible output appears on the see-through image displays180C-D of optical assembly 180A-B, which is driven by image displaydriver 934 to present the sequence of displayed images, including theinitial displayed image with the initial field of view and thesuccessive displayed image with the successive field of view.

As shown in FIG. 9 , high-speed circuitry 930 includes high-speedprocessor 932, memory 934, and high-speed wireless circuitry 936. In theexample, the image display driver 942 is coupled to the high-speedcircuitry 930 and operated by the high-speed processor 932 in order todrive the left and right image displays 180C-D of the optical assembly180A-B, including the mirrors 802 of display 800 shown in FIG. 8A. Theimage display driver 942 selectively controls each mirror 802 ofsee-through display 800 to produce the virtual image. High-speedprocessor 932 may be any processor capable of managing high-speedcommunications and operation of any general computing system needed foreyewear device 100. High-speed processor 932 includes processingresources needed for managing high-speed data transfers on high-speedwireless connection 937 to a wireless local area network (WLAN) usinghigh-speed wireless circuitry 936. In certain examples, the high-speedprocessor 932 executes an operating system such as a LINUX operatingsystem or other such operating system of the eyewear device 100 and theoperating system is stored in memory 934 for execution. In addition toany other responsibilities, the high-speed processor 932 executing asoftware architecture for the eyewear device 100 is used to manage datatransfers with high-speed wireless circuitry 936. In certain examples,high-speed wireless circuitry 936 is configured to implement Instituteof Electrical and Electronic Engineers (IEEE) 802.11 communicationstandards, also referred to herein as Wi-Fi. In other examples, otherhigh-speed communications standards may be implemented by high-speedwireless circuitry 936.

Low-power wireless circuitry 924 and the high-speed wireless circuitry936 of the eyewear device 100 can include short range transceivers(Bluetooth™) and wireless wide, local, or wide area network transceivers(e.g., cellular or WiFi). Mobile device 990, including the transceiverscommunicating via the low-power wireless connection 925 and high-speedwireless connection 937, may be implemented using details of thearchitecture of the eyewear device 100, as can other elements of network995.

Memory 934 includes any storage device capable of storing various dataand applications, including, among other things, color maps, camera datagenerated by the left and right visible light cameras 114A-B and theimage processor 912, as well as images generated for display by theimage display driver 942 on the see-through image displays 180C-D of theoptical assembly 180A-B. While memory 934 is shown as integrated withhigh-speed circuitry 930, in other examples, memory 934 may be anindependent standalone element of the eyewear device 100. In certainsuch examples, electrical routing lines may provide a connection througha chip that includes the high-speed processor 932 from the imageprocessor 912 or low-power processor 922 to the memory 934. In otherexamples, the high-speed processor 932 may manage addressing of memory934 such that the low-power processor 922 will boot the high-speedprocessor 932 any time that a read or write operation involving memory934 is needed.

Server system 998 may be one or more computing devices as part of aservice or network computing system, for example, that include aprocessor, a memory, and network communication interface to communicateover the network 995 with the mobile device 990 and eyewear device 100.Eyewear device 100 is connected with a host computer. For example, theeyewear device 100 is paired with the mobile device 990 via thehigh-speed wireless connection 937 or connected to the server system 998via the network 995.

Output components of the eyewear device 100 include visual components,such as the left and right image displays 180C-D of optical assembly180A-B as described in FIGS. 2C-D (e.g., a display such as a liquidcrystal display (LCD), a plasma display panel (PDP), a light emittingdiode (LED) display, a projector, or a waveguide). The image displays180C-D of the optical assembly 180A-B are driven by the image displaydriver 942. The output components of the eyewear device 100 furtherinclude acoustic components (e.g., speakers), haptic components (e.g., avibratory motor), other signal generators, and so forth. The inputcomponents of the eyewear device 100, the mobile device 990, and serversystem 998, may include alphanumeric input components (e.g., a keyboard,a touch screen configured to receive alphanumeric input, a photo-opticalkeyboard, or other alphanumeric input components), point-based inputcomponents (e.g., a mouse, a touchpad, a trackball, a joystick, a motionsensor, or other pointing instruments), tactile input components (e.g.,a physical button, a touch screen that provides location and force oftouches or touch gestures, or other tactile input components), audioinput components (e.g., a microphone), and the like.

Eyewear device 100 may optionally include additional peripheral deviceelements 919. Such peripheral device elements may include biometricsensors, additional sensors, or display elements integrated with eyeweardevice 100. For example, peripheral device elements 919 may include anyI/O components including output components, motion components, positioncomponents, or any other such elements described herein. The eyeweardevice 100 can take other forms and may incorporate other types offrameworks, for example, a headgear, a headset, or a helmet.

For example, the biometric components of the user interface field ofview adjustment 900 include components to detect expressions (e.g., handexpressions, facial expressions, vocal expressions, body gestures, oreye tracking), measure biosignals (e.g., blood pressure, heart rate,body temperature, perspiration, or brain waves), identify a person(e.g., voice identification, retinal identification, facialidentification, fingerprint identification, or electroencephalogrambased identification), and the like. The motion components includeacceleration sensor components (e.g., accelerometer), gravitation sensorcomponents, rotation sensor components (e.g., gyroscope), and so forth.The position components include location sensor components to generatelocation coordinates (e.g., a Global Positioning System (GPS) receivercomponent), WiFi or Bluetooth™ transceivers to generate positioningsystem coordinates, altitude sensor components (e.g., altimeters orbarometers that detect air pressure from which altitude may be derived),orientation sensor components (e.g., magnetometers), and the like. Suchpositioning system coordinates can also be received over wirelessconnections 925 and 937 from the mobile device 990 via the low-powerwireless circuitry 924 or high-speed wireless circuitry 936.

According to some examples, an “application” or “applications” areprogram(s) that execute functions defined in the programs. Variousprogramming languages can be employed to produce one or more of theapplications, structured in a variety of manners, such asobject-oriented programming languages (e.g., Objective-C, Java, or C++)or procedural programming languages (e.g., C or assembly language). In aspecific example, a third party application (e.g., an applicationdeveloped using the ANDROID™ or IOS™ software development kit (SDK) byan entity other than the vendor of the particular platform) may bemobile software running on a mobile operating system such as IOS™,ANDROID™, WINDOWS® Phone, or another mobile operating systems. In thisexample, the third-party application can invoke API calls provided bythe operating system to facilitate functionality described herein.

Referring to FIG. 10 , the processor 932 presents images to the user onthe image displays 180 using the image processor 912 and the imagedisplay driver 942. The processor 932 develops and presents the visualimages via the image displays responsive to the location of the eyeweardevice 100 within the environment 600. In one example, the visual imagesinclude an image of a hand 1002 for manipulating features of a graphicaluser interface (GUI) and a virtual space craft 1004.

The GUI may be presented on the display 180 of the eyewear device 100,the display of the mobile device 990, or a display for a remote computersuch as the server system 998. In one example, a user may manipulateselectors and actuate the buttons using a user input device of theeyewear device 100, using a user input layer of the mobile device 990,or a user input of another device.

In another example, a user may manipulate the selectors and actuate thebuttons through hand gestures captured by the cameras 114 of the eyeweardevice 100. In accordance with this example, the processor 932 of aneyewear device 100 is configured to capture frames of video data withcamera 114A, 114B. Objects in the images are compared to the handgesture library 980 to identify predefined hand gestures (e.g., apointing index finger) associated with an action. When a hand gesture isidentified, its position is determined with respect to the selectors andactuate the buttons. A modification of the hand gesture (e.g., a tappingmotion when the tip of the index finger is near a button or a swipingmotion when the tip of the index finger is near a selector) results inan actuation of the buttons/selector.

The process of determining whether a detected hand shape matches apredefined gesture, in some implementations, involves comparing thepixel-level data about the hand shape in one or more captured frames ofvideo data to a collection of hand gestures stored in a hand gesturelibrary 980 (FIG. 9 ). The detected hand shape data may includethree-dimensional coordinates for the wrist, up to fifteeninterphalangeal joints, up five fingertips, and other skeletal orsoft-tissue landmarks found in a captured frame. These data are comparedto hand gesture data stored in the hand gesture library 980 until thebest match is found. In some examples, the process includes calculatingthe sum of the geodesic distances between the detected hand shapefingertip coordinates and a set of fingertip coordinates for each handgesture stored in the library 980. A sum that is within a configurablethreshold accuracy value represents a match.

In another example implementation, the process of determining whether adetected hand shape matches a predefined gesture, involves using amachine-learning algorithm to compare the pixel-level data about thehand shape in one or more captured frames of video data to a collectionof images that include hand gestures.

Machine learning refers to an algorithm that improves incrementallythrough experience. By processing a large number of different inputdatasets, a machine-learning algorithm can develop improvedgeneralizations about particular datasets, and then use thosegeneralizations to produce an accurate output or solution whenprocessing a new dataset. Broadly speaking, a machine-learning algorithmincludes one or more parameters that will adjust or change in responseto new experiences, thereby improving the algorithm incrementally; aprocess similar to learning.

In the context of computer vision, mathematical models attempt toemulate the tasks accomplished by the human visual system, with the goalof using computers to extract information from an image and achieve anaccurate understanding of the contents of the image. Computer visionalgorithms have been developed for a variety of fields, includingartificial intelligence and autonomous navigation, to extract andanalyze data in digital images and video.

Deep learning refers to a class of machine-learning methods that arebased on or modeled after artificial neural networks. An artificialneural network is a computing system made up of a number of simple,highly interconnected processing elements (nodes), which processinformation by their dynamic state response to external inputs. A largeartificial neural network might have hundreds or thousands of nodes.

A convolutional neural network (CNN) is a type of neural network that isfrequently applied to analyzing visual images, including digitalphotographs and video. The connectivity pattern between nodes in a CNNis typically modeled after the organization of the human visual cortex,which includes individual neurons arranged to respond to overlappingregions in a visual field. A neural network that is suitable for use inthe determining process described herein is based on one of thefollowing architectures: VGG16, VGG19, ResNet50, Inception V3, Xception,or other CNN-compatible architectures.

In the machine-learning example, the processor 932 determines whether adetected hand shape substantially matches a predefined gesture using amachine-trained algorithm referred to as a hand feature model. Theprocessor 932 is configured to access the hand feature model, trainedthrough machine learning, and applies the hand feature model to identifyand locate features of the hand shape in one or more frames of the videodata.

In one example implementation, the trained hand feature model receives aframe of video data which contains a detected hand shape and abstractsthe image in the frame into layers for analysis. Data in each layer iscompared to hand gesture data stored in the hand gesture library 980,layer by layer, based on the trained hand feature model, until a goodmatch is identified.

In one example, the layer-by-layer image analysis is executed using aconvolutional neural network. In a first convolution layer, the CNNidentifies learned features (e.g., hand landmarks, sets of jointcoordinates, and the like). In a second convolution layer, the image istransformed into a plurality of images, in which the learned featuresare each accentuated in a respective sub-image. In a pooling layer, thesizes and resolution of the images and sub-images are reduced in orderisolation portions of each image that include a possible feature ofinterest (e.g., a possible palm shape, a possible finger joint). Thevalues and comparisons of images from the non-output layers are used toclassify the image in the frame. Classification, as used herein, refersto the process of using a trained model to classify an image accordingto the detected hand shape. For example, an image may be classified as“pointer gesture present” if the detected hand shape matches the pointergesture from the library 480.

In some example implementations, the processor 932, in response todetecting a pointing gesture, presents on the display 180A-B anindicator 1002 (see FIG. 10 ). The indicator 1002 informs the wearerthat a predefined gesture has been detected. The indicator 1002 in oneexample is an object, such as the pointing finger shown in FIG. 10 . Theindicator 1002 may include one or more visible, audible, tactile, andother elements to inform or alert the wearer that a pointer gesture hasbeen detected. A user may move the indicator 1002 by moving the detectedhand gesture within the field of view of the eyewear device 100.

It will be understood that the terms and expressions used herein havethe ordinary meaning as is accorded to such terms and expressions withrespect to their corresponding respective areas of inquiry and studyexcept where specific meanings have otherwise been set forth herein.Relational terms such as first and second and the like may be usedsolely to distinguish one entity or action from another withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities or actions. The terms “comprises,” “comprising,”“includes,” “including,” or any other variation thereof, are intended tocover a non-exclusive inclusion, such that a process, method, article,or apparatus that comprises or includes a list of elements or steps doesnot include only those elements or steps but may include other elementsor steps not expressly listed or inherent to such process, method,article, or apparatus. An element preceded by “a” or “an” does not,without further constraints, preclude the existence of additionalidentical elements in the process, method, article, or apparatus thatcomprises the element.

Unless otherwise stated, any and all measurements, values, ratings,positions, magnitudes, sizes, and other specifications that are setforth in this specification, including in the claims that follow, areapproximate, not exact. Such amounts are intended to have a reasonablerange that is consistent with the functions to which they relate andwith what is customary in the art to which they pertain. For example,unless expressly stated otherwise, a parameter value or the like mayvary by as much as ±10% from the stated amount.

In addition, in the foregoing Detailed Description, it can be seen thatvarious features are grouped together in various examples for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimed examplesrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, the subject matter to be protected liesin less than all features of any single disclosed example. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separately claimed subjectmatter.

While the foregoing has described what are considered to be the bestmode and other examples, it is understood that various modifications maybe made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that they may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim any and allmodifications and variations that fall within the true scope of thepresent concepts.

What is claimed is:
 1. Eyewear, comprising: a frame; a temple coupled to the frame; and a display supported by the frame, wherein the display comprises a first layer configured to generate an image, and a second layer and a third layer positioned on opposing sides of the first layer, wherein the second layer and the third layer are each attached to the first layer by a respective adhesive positioned an offset distance inward from an outer edge of the first layer, wherein the offset distance of the adhesive is at least double a thickness of the first layer.
 2. The eyewear as specified in claim 1, wherein there is no adhesive positioned between the second layer and the first layer, and between the third layer and the first layer, at the outer edge of the first layer.
 3. The eyewear as specified in claim 2, wherein the first layer is an optical waveguide.
 4. The eyewear as specified in claim 2, wherein the second layer and the third layer are each substrates.
 5. The eyewear as specified in claim 4, wherein the substrates each comprise an optically transparent glass substrate.
 6. The eyewear as specified in claim 4, further comprising an air gap between the substrates and the first layer.
 7. The eyewear as specified in claim 1, wherein the display is attached to the frame by an adhesive positioned inward from an outer edge of the second layer.
 8. A display configured for use with eyewear having a frame and a temple coupled to the frame, comprising: a first layer configured to generate an image; and a second layer and a third layer positioned on opposing sides of the first layer, wherein the second layer and the third layer are each attached to the first layer by a respective adhesive positioned an offset distance inward from an outer edge of the first layer, wherein the offset distance of the adhesive is at least double a thickness of the first layer.
 9. The display as specified in claim 8, wherein there is no adhesive positioned between the second layer and the first layer, and between the third layer and the first layer, at the outer edge of the first layer.
 10. The display as specified in claim 9, wherein the first layer is an optical waveguide.
 11. The display as specified in claim 9, wherein the second layer and the third layer are each substrates.
 12. The display as specified in claim 11, wherein the substrates each comprise an optically transparent glass substrate.
 13. The display as specified in claim 11, further comprising an air gap between the substrates and the first layer.
 14. The display as specified in claim 8, wherein the display is attached to an eyewear frame by an adhesive positioned inward from an outer edge of the second layer.
 15. A method of producing eyewear having a frame, a temple coupled to the frame, and a display comprising a first layer configured to generate an image, and a second layer and a third layer positioned on opposing sides of the first layer, comprising; disposing a first adhesive between the first layer and the second layer, the first adhesive positioned an offset distance inward from an outer edge of the first layer; coupling the first layer to the second layer; disposing a second adhesive between the first layer and the third layer, the second adhesive positioned an offset distance inward from an outer edge of the first layer, wherein the offset distance of the adhesive is at least double a thickness of the first layer; coupling the first layer to the third layer; and coupling the display to the eyewear frame.
 16. The method as specified in claim 15, wherein there is no adhesive positioned between the second layer and the first layer, and between the third layer and the first layer, at the outer edge of the first layer.
 17. The method as specified in claim 16, wherein the first layer is an optical waveguide.
 18. The method as specified in claim 17, wherein the second layer and the third layer are each substrates. 